Greenhouse Gas Levels Hit New Record

11/21/2012 1:42 AM ET

The concentration of greenhouse gases like carbon dioxide, methane and nitrous oxide in the atmosphere, responsible for global warming, reached a new record high in 2011, according to an annual bulletin released Tuesday by the World Meteorological Organization.

About 375 billion tonnes of carbon have been released into the atmosphere as carbon dioxide, primarily from fossil fuel combustion since the start of the industrial era in 1750, adds the WMO's 2011 Greenhouse Gas Bulletin.

According to the report, the amount of carbon dioxide in the atmosphere, the most important greenhouse gas, rose to 390.9 parts per million (ppm) in 2011, which is 2.0 ppm higher than in 2010 and 140% of the pre-industrial level.

Methane, the second most important greenhouse gas, reached a new high of about 1813 parts per billion (ppb) in 2011, or 259% of the pre-industrial level.

The amount of nitrous oxide in the atmosphere in 2011 was about 324.2 parts per billion, which is 1.0 ppb above the previous year and 120% of the pre-industrial level.

Note that the numbers represent the concentrations - and not emissions, of greenhouse gases. The report defines concentrations as what remains in the atmosphere after the complex system of interactions between the atmosphere, biosphere and the oceans, and emissions as what goes into the atmosphere.

WMO Secretary-General Michel Jarraud pointed out, "We have already seen that the oceans are becoming more acidic as a result of the carbon dioxide uptake, with potential repercussions for the underwater food chain and coral reefs. There are many additional interactions between greenhouse gases, Earth's biosphere and oceans, and we need to boost our monitoring capability and scientific knowledge in order to better understand these."